There are several methods known for the manufacture of cellular ceramic materials involving foaming. Examples are:    a) insertion (incorporation e.g. injection) and mechanical distribution of gases in a low viscosity melt.    b) Release and expansion of dissolved gases in a low viscosity melt under vacuum.    c) Insertion (incorporation) of foaming agents in a melt.    d) Mixing glass powder with a foam agent and subsequent heating.
In the case of the last glass foaming process, the manufacturing equipment typically comprises a foaming furnace with a belt carrying the glass powder and foam, and a powder loading apparatus. The foaming involves the foaming of either thick or thin plates.